The purpose of this exploratory research study is to learn more about the latent effects of different modes of care in infancy on preschool children whose mothers entered the workforce before their children were 12 months of age. This study is intended to be the first in a series of investigations preliminary to a large- scale effort to document the effects of diverse rearing conditions in the first year of life on children's activities and competences at preschool age. The central purpose of this project is to pinpoint significant variables to be examined in greater detail in the subseqent prospective study. Data are being gathered on a homogeneous, low-risk population and include measures of cognitive, social, and behavioral development.